Lennox, the dog at the centre of an international campaign to stop a Northern Ireland council from putting him to sleep, has been destroyed.

The dog's heartbroken owner, Caroline Barnes, said her teenage daughter Brooke had been denied the chance to say a final farewell.

"We had told Brooke that even if we don't win (the case), she can still see Lennox, have her last pictures with him and say goodbye," said Ms Barnes.

"To then have to tell her that no, that is not happening, it has been extremely unfair."

The family has been told the dog's body will not be returned but they will receive his ashes.

Last night Lennox supporters staged a protest in Spain, following similar rallies in New York and Serbia.

Ms Barnes said: "We can draw a bit of comfort from all of the brilliant friends that we have made."

The family pet was put down this morning after the expiry of a midnight deadline for legal appeals.

Campaigners claim to have 200,000 signatures supporting a reprieve and emotions were running high.

A Belfast City Council spokesman said: "Lennox, an illegal pit-bull terrier type, has been humanely put to sleep. This was in accordance with the Order of the County Court which was affirmed by the Northern Ireland Court of Appeal.

"Whilst there is an exemption scheme to which dogs of this type (pit-bull terrier type) may be admitted as an alternative to destruction, there were no such measures that could be applied in this case that would address the concerns relating to public safety. The Council’s expert described the dog as one of the most unpredictable and dangerous dogs he had come across.

"Over the past two years, Council officials have been subjected to a sustained campaign of abuse including threats of violence and death threats. The Council has been in ongoing contact with the PSNI in relation to that.

"The Council regrets that the court action was necessary but would emphasise that the safety of the public remains its key priority."

Lennox was impounded by Belfast City Council's dog wardens in 2010.

In June, Northern Ireland's most senior judges rejected Caroline Barnes' legal bid to overturn an order for the destruction of her pet.

Ms Barnes, who is disabled, and her family insisted that Lennox was not dangerous, and while it was not clear exactly what breed he was, pit bulls and dogs like them are illegal in Northern Ireland.

Two lower courts had already ruled that the dog should be put down.

The dog was seized by Belfast City Council dog wardens in May 2010. He was assessed to be a danger to the public and subsequently ordered to be put down.

A former Metropolitan Police dog handler claimed the dog represented a danger due to his unpredictability.

Ms Barnes, 35, had accepted her pet was a pit-bull type, but claimed there had been a failure to properly consider a possible exemption scheme.

Her battle for Lennox became an international campaign to save his life. It went "viral" on social media websites and attracted tens of thousands of well-wishers.

Well-known people including boxer Lennox Lewis and Assembly First Minister Peter Robinson were among those who used Twitter to call for the dog to be spared.